I. Field
The present invention relates to a system for monitoring and annunciating leakage of gas vapors and/or volatile material from a volatile material compressor.
II. Background
A volatile material (gas) compressor is a pressure vessel in which a piston, moved by a compressor piston rod, compresses a volume of volatile material by decreasing the space in which the volatile material is contained. As the pressure increases, the higher pressure volatile material attempts to escape along the surface of the compressor piston rod and out of the compressor cylinder through the opening for the compressor piston rod. Packing material, which may take the form of a series of special rings, contained in a packing case, surrounds the compressor piston rod and impedes the volatile material from escaping into the environment.
When the packing material comprises rings, the efficiency of the rings is determined by several factors which include the conditions of the compressor piston, the compressor piston rod, the packing case and the rings, themselves. Wear of the packing rings is expected, and the timing of their replacement is crucial to efficient operation of the compressor apparatus and other compressor equipment.
We observe that regulatory requirements in the area of pollution prevention are becoming more and more stringent. Depending on the particular volatile material being compressed, for example, a volatile material (VOC) which may be regulated by the Environmental Protection Agency (EPA), leaks of escaping VOCs from a compressor apparatus can represent significant loss of revenue and could trigger possible environmental fines for the compressor operator.
Similarly, national emission standards for hazardous air pollutants (NESHAP) established pursuant to Section 112 of the Clean Air Act (as amended Nov. 15, 1990) regulate specific categories of stationary sources that emit (or have the potential to emit) one or more hazardous air pollutants (HAPs) (see generally Title 40 of the Code of Federal Regulations). Some examples of HAPs include formaldehyde, benzene, 1,3-butadiene, acrolein, acetaldehyde, and toluene (see larger illustrative list in Table 1). Similarly, a set of pollutants commonly referred to as “Criteria Pollutants” face regulatory scrutiny. These pollutants are generated by combustion and include Nitrous Oxides (NOx), Carbon Monoxide (CO) and Volatile Organic Compounds (VOCs). These compounds are regulated by the New Source Performance Standards (NSPS). A third set of regulated (or potentially soon-to-be regulated) gases are greenhouse gases (GHG), for example, methane and carbon dioxide.
TABLE 1Illustrative List of Hazardous Air Pollutants.CASChemicalNumberName75070Acetaldehyde60355Acetamide75058Acetonitrile98862Acetophenone539632-Acetylaminofluorene107028Acrolein79061Acrylamide79107Acrylic acid107131Acrylonitrile107051Allyl chloride926714-Aminobiphenyl62533Aniline90040o-Anisidine1332214 Asbestos71432Benzene (including benzene from gasoline)92875Benzidine98077Benzotrichloride100447Benzyl chloride92524Biphenyl117817Bis(2-ethylhexyl)phthalate (DEHP)542881Bis(chloromethyl)ether75252Bromoform1069901,3-Butadiene156627Calcium cyanamide105602Caprolactam133062Captan63252Carbaryl75150Carbon disulfide56235Carbon tetrachloride463581Carbonyl sulfide120809Catechol133904Chloramben57749Chlordane7782505Chlorine79118Chloroacetic acid5322742-Chloroacetophenone108907Chlorobenzene510156Chlorobenzilate67663Chloroform107302Chloromethyl methyl ether126998Chloroprene1319773Cresols/Cresylic acid (isomers and mixture)95487o-Cresol108394m-Cresol106445p-Cresol98828Cumene947572,4-D, salts and esters3547044DDE334883Diazomethane132649Dibenzofurans961281,2-Dibromo-3-chloropropane84742Dibutylphthalate1064671,4-Dichlorobenzene(p)919413,3-Dichlorobenzidene111444Dichloroethyl ether (Bis(2-chloroethyl)ether)5427561,3-Dichloropropene62737Dichlorvos111422Diethanolamine121697N,N-Dimethylaniline64675Diethyl sulfate1199043,3-Dimethoxybenzidine60117Dimethyl aminoazobenzene1199373,3′-Dimethyl benzidine79447Dimethyl carbamoyl chloride68122Dimethyl formamide571471,1-Dimethyl hydrazine131113Dimethyl phthalate77781Dimethyl sulfate5345214,6-Dinitro-o-cresol, and salts512852,4-Dinitrophenol1211422,4-Dinitrotoluene1239111,4-Dioxane (1,4-Diethyleneoxide)1226671,2-Diphenylhydrazine106898Epichlorohydrin (1-Chloro-2,3-epoxypropane)1068871,2-Epoxybutane140885Ethyl acrylate100414Ethyl benzene51796Ethyl carbamate (Urethane)75003Ethyl chloride (Chloroethane)106934Ethylene dibromide (Dibromoethane)107062Ethylene dichloride (1,2-Dichloroethane)107211Ethylene glycol151564Ethylene imine (Aziridine)75218Ethylene oxide96457Ethylene thiourea75343Ethylidene dichloride (1,1-Dichloroethane)50000Formaldehyde76448Heptachlor118741Hexachlorobenzene87683Hexachlorobutadiene77474Hexachlorocyclopentadiene67721Hexachloroethane822060Hexamethylene-1,6-diisocyanate680319Hexamethylphosphoramide110543Hexane302012Hydrazine7647010Hydrochloric acid7664393Hydrogen fluoride (Hydrofluoric acid)7783064Hydrogen sulfide123319Hydroquinone78591Isophorone58899Lindane (all isomers)108316Maleic anhydride67561Methanol72435Methoxychlor74839Methyl bromide (Bromomethane)74873Methyl chloride (Chloromethane)71556Methyl chloroform (1,1,1-Trichloroethane)78933Methyl ethyl ketone (2-Butanone)60344Methyl hydrazine74884Methyl iodide (Iodomethane)108101Methyl isobutyl ketone (Hexone)624839Methyl isocyanate80626Methyl methacrylate1634044 Methyl tert butyl ether1011444,4-Methylene bis (2-chloroaniline)75092Methylene chloride (Dichloromethane)101688Methylene diphenyl diisocyanate (MDI)1017794,4′-Methylenedianiline91203Naphthalene98953Nitrobenzene929334-Nitrobiphenyl1000274-Nitrophenol794692-Nitropropane684935N-Nitroso-N-methylurea62759N-Nitrosodimethylamine59892N-Nitrosomorpholine56382Parathion82688Pentachloronitrobenzene (Quintobenzene)87865Pentachlorophenol108952Phenol106503p-Phenylenediamine75445Phosgene7803512Phosphine7723140Phosphorus85449Phthalic anhydride1336363Polychlorinated biphenyls (Aroclors)11207141,3-Propane sultone57578beta-Propiolactone123386Propionaldehyde114261Propoxur (Baygon)78875Propylene dichloride (1,2-Dichloropropane)75569Propylene oxide755581,2-Propylenimine (2-Methyl aziridine)91225Quinoline106514Quinone100425Styrene96093Styrene oxide17460162,3,7,8-Tetrachlorodibenzo-p-dioxin793451,1,2,2-Tetrachloroethane127184Tetrachloroethylene (Perchloroethylene)7550450Titanium tetrachloride108883Toluene958072,4-Toluene diamine5848492,4-Toluene diisocyanate95534o-Toluidine8001352Toxaphene (chlorinated camphene)1208211,2,4-Trichlorobenzene790051,1,2-Trichloroethane79016Trichloroethylene959542,4,5-Trichlorophenol880622,4,6-Trichlorophenol121448Triethylamine1582098 Trifluralin5408412,2,4-Trimethylpentane108054Vinyl acetate593602Vinyl bromide75014Vinyl chloride75354Vinylidene chloride (1,1-Dichloroethylene)1330207Xylenes (isomers and mixture)95476o-Xylenes108383m-Xylenes106423p-Xylenes0Antimony Compounds0Arsenic Compounds (inorganic including arsine)0Beryllium Compounds0Cadmium Compounds0Chromium Compounds0Cobalt Compounds0Coke Oven Emissions0Cyanide Compounds10Glycol ethers20Lead Compounds0Manganese Compounds0Mercury Compounds0Fine mineral fibers30Nickel Compounds0Polycylic Organic Matter40Radionuclides (including radon)50Selenium CompoundsNOTE:For all listings above which contain the word “compounds” and for glycol ethers, the following applies: Unless otherwise specified, these listings are defined as including any unique chemical substance that contains the named chemical (i.e., antimony, arsenic, etc.) as part of that chemical's infrastructure.1X′CN where X = H′ or any other group where a formal dissociation may occur. For example KCN or Ca(CN)22Includes mono- and di- ethers of ethylene glycol, diethylene glycol, and triethylene glycol R—(OCH2CH2)n—OR′ where: n = 1, 2, or 3 R = alkyl or aryl groups R′ = R, H, or groups which, when removed, yield glycol ethers with the structure: R—(OCH2CH)n—OH. Polymers are excluded from the glycol category.3Includes mineral fiber emissions from facilities manufacturing or processing glass, rock, or slag fibers (or other mineral derived fibers) of average diameter 1 micrometer or less.4Includes organic compounds with more than one benzene ring, and which have a boiling point greater than or equal to 100° C.5A type of atom which spontaneously undergoes radioactive decay.
A business that fails to monitor and take appropriate action to correct leaks of volatile organic compounds (VOCs), hazardous air pollutants (HAPs), Criteria Pollutants or greenhouse gases (GHGs) is taking a risk of having their operating permits suspended in addition to the possibility of incurring significant fines. As used herein, the term “volatile material” includes, without limitation, VOCs, HAPs, Criteria Pollutants and GHGs.
In addition to regulatory concerns, we speculate that the lost revenue of escaping VOCs and other volatile materials at the site of compression of these gases is a significant incentive to monitor compressor equipment to enable quick repair or replacement of compressor equipment in the event of detected volatile material leaks.
Currently within the industry, we have sometimes observed that the decision by the compressor operator regarding the timing of maintenance is left to either audible detection of volatile material leaks or physical detection of escaping gas by placement of the operator's hand on the compressor apparatus (to detect the stream of the escaping volatile material). Thus, there is a continuing need for a system that can reliably monitor and annunciate emissions of equipment, such as compressors of volatile materials such as VOCs.